Class 10 Science • Complete Chapter Notes
Metals and non-metals are two broad categories of elements. They differ in their physical properties, chemical behaviour, tendency to lose or gain electrons and the compounds they form.
Metals such as iron, copper, aluminium and zinc are widely used in daily life and industry, while non-metals such as oxygen, nitrogen, sulphur and chlorine have many important biological and industrial uses.
Metals generally show the following physical properties. There are exceptions, so these should be understood as general trends rather than universal rules.
Metals generally react with oxygen to form metal oxides.
Magnesium oxide is a basic oxide and reacts with acids to form salt and water.
Some metal oxides react with both acids and bases. Such oxides are called amphoteric oxides.
Zinc oxide is an important example of an amphoteric oxide.
Many non-metals react with oxygen to form non-metal oxides. These oxides are generally acidic in nature.
Carbon dioxide is a non-metal oxide and shows acidic behaviour.
Different metals react with water with different intensities. Some react vigorously while others react only with steam or do not react under ordinary conditions.
Sodium and potassium react very vigorously with water and produce hydrogen gas along with the corresponding hydroxide.
Iron reacts with steam rather than cold water in the conditions usually discussed in this chapter.
Metals above hydrogen in the reactivity series generally react with dilute acids to produce salt and hydrogen gas.
Metals such as copper do not liberate hydrogen from dilute hydrochloric acid because copper is below hydrogen in the reactivity series.
A more reactive metal can displace a less reactive metal from its salt solution.
Iron is more reactive than copper, so iron displaces copper from copper sulphate solution.
The reactivity series arranges metals in decreasing order of their tendency to participate in chemical reactions.
Potassium and sodium are among the most reactive metals in this commonly used series, while gold is among the least reactive.
Metals tend to lose electrons and form positive ions, whereas non-metals tend to gain electrons and form negative ions. The electrostatic attraction between oppositely charged ions leads to ionic bonding.
Sodium has one valence electron and tends to lose it. Chlorine tends to gain one electron.
The resulting Na⁺ and Cl⁻ ions attract each other to form sodium chloride.
Metals occur in the Earth's crust in different forms. Some occur in the native or free state, while many occur in the form of compounds.
Naturally occurring substances containing metals or their compounds are called minerals.
Minerals from which metals can be extracted conveniently and economically are called ores.
The extraction process depends mainly on the reactivity of the metal.
Highly reactive, moderately reactive and low-reactivity metals require different extraction strategies.
Metals low in the reactivity series may occur in relatively uncombined form or can be obtained by comparatively simple reduction processes.
Cinnabar, an ore of mercury, is heated in air to form mercury(II) oxide. Further heating gives mercury.
Metals such as zinc, iron and lead are commonly extracted by converting their ores to oxides and then reducing the oxides using suitable reducing agents.
Carbon or carbon monoxide may act as reducing agents for suitable metal oxides.
Highly reactive metals such as sodium, potassium, calcium, magnesium and aluminium cannot generally be obtained by reduction with carbon because their compounds are very stable.
These metals are extracted mainly by electrolysis of their molten compounds.
Electrical energy drives the decomposition of the molten ionic compound.
Aluminium is a highly reactive metal and is extracted by electrolytic methods from purified aluminium oxide.
Cryolite is used in the electrolytic extraction process to lower the melting point of the mixture and improve its conductivity.
In the electrolytic cell, aluminium ions are reduced at the cathode to form aluminium metal.
Corrosion is the gradual deterioration of a metal as a result of chemical or electrochemical reactions with its surroundings.
Iron reacts with oxygen and moisture over time to form rust, a hydrated form of iron(III) oxide.
Corrosion can be reduced by preventing the metal from coming into contact with air, moisture or other corrosive substances.
In galvanisation, iron or steel is coated with a protective layer of zinc.
An alloy is a homogeneous mixture of two or more metals or of a metal and a non-metal.
| Alloy | Main Components |
|---|---|
| Brass | Copper + Zinc |
| Bronze | Copper + Tin |
| Solder | Lead + Tin |
| Stainless Steel | Mainly Iron + Chromium + Nickel + Carbon |
Metals combine useful properties such as strength, conductivity, ductility, malleability and, in many cases, durability. These properties make them useful in construction, electrical systems, transport, tools, machines and household products.
| Property | Metals | Non-Metals |
|---|---|---|
| Lustre | Generally lustrous | Generally dull |
| Malleability | Generally malleable | Generally brittle |
| Ductility | Generally ductile | Generally non-ductile |
| Electrical Conductivity | Generally good | Generally poor |
| Chemical Tendency | Tend to lose electrons | Tend to gain or share electrons |
Metals generally form positive ions by losing electrons, whereas non-metals commonly gain or share electrons.
The tendency to lose or gain electrons is related to atomic structure, atomic size and effective nuclear attraction.
For curriculum-aligned preparation, students should refer to the official CBSE Academic material and NCERT textbook resources.
CBSE Science Reading Material 2026-27 → NCERT Official Textbooks → CBSE Academic Curriculum 2026-27 →